The present invention pertains to a method for treating a pulmonary disease state in mammals by altering indigenous in vivo levels of nitric oxide in mammalian cells.
The disclosures referred to herein to illustrate the background of the invention and to provide additional detail with respect to its practice are incorporated herein by reference and, for convenience, are referenced in the following text and respectively grouped in the appended bibliography.
Nitric oxide (NO), an oxidation product of nitrogen, is produced normally by many cell types, including endothelial cells and macrophages. Nitric oxide has functions ranging from neurotransmission to vasodilatation. Nitric oxide also produces clinically useful bronchodilation (1) and is also used by the body to kill bacteria, fungal infections, viral infections, and tumors. Nitric oxide can kill these cell types because bacterial, viral, and tumor cells have no defenses against nitric oxide. Normal mammalian cells can cope with normal levels of nitric oxide by using enzyme systems to use or deactivate elevated cellular levels of nitric oxide (28-32). Nitric oxide is the main mediator of the tumoricidal action of activated macrophages (29-32). While over 30,000 papers have been written to date on nitric oxide, the role of nitric oxide in tumor biology is not completely understood. Nitric oxide appears to have both tumor promoting and inhibiting effects (31). Recent publications have implicated the reactive oxygen species made from nitric oxide during the inflammatory process as being the tumor promoting agents, not nitric oxide itself (28).
Nitric oxide has been used successfully in patients with persistent fetal circulation, persistent pulmonary hypertension in newborn (11), pulmonary hypertension secondary to cardiac dysfunction or surgery, and with adult respiratory distress syndrome (ARDS) (1,2). Nitric oxide can become a toxic oxidant when it reacts with excess oxygen radicals to produce nitrogen dioxide (NO2) (1-3) and peroxynitrite (ONOO). Oxygen radicals, such as superoxide (O2) and hydrogen peroxide, destroy nitric oxide and produce the toxic NO2 and peroxynitrite (1-3). Peroxynitrite ion and peroxynitrous acid, formed from the interaction of nitric oxide and superoxide anions, are strong oxidant species that work against nitric oxide by inducing single-strand breaks in DNA and enhancing tumor formation and growth (28) rather than death. Superoxide and hydrogen peroxide also cause vascular constriction (1). H2O2 is the oxygen radical that appears to have the major effect on airway tone and causes contraction in both bovine and guinea pig airways.(14,15). H2O2 markedly potentiates the cytotoxic effects of eosinophil derived enzymes such as 5,8,11,14,17-eicosapentaenoic acid (16). Excess superoxide anions and hydrogen peroxide, produced during the inflammatory phase of an injury, will destroy healthy tissue surrounding the site and will mitigate the positive bronchodilation effect of nitric oxide (26). Oxygen radicals can also initiate lipid peroxidation employing arachidonic acid as an substrate producing prostaglandins and leukotrienes. H2O2 can induce arachidonic acid metabolism in alveolar macrophages (17,26). Oxygen radicals also produce 8-isoprostanes which are potent renal and pulmonary artery vasoconstrictors, bronchoconstrictors, and induce airflow obstructions (26, 27). Because oxygen radicals contribute to the instability of nitric oxide, the addition of superoxide dismutase (SOD) or catalase (15) or Vitamin E (28) protect nitric oxide to produce its desired bronchodilation (2). Hydrogen peroxide is elevated in patients with chronic obstructive pulmonary disease (COPD), asthma, and ARDS (26). A study in 28 patients showed a significant correlation between oxygen radical generation in white blood cell count (WBC) and the degree of bronchial hyperreactivity in vivo in nonallergic patient""s (18). The authors suggested that direct suppression of oxygen radical production by corticosteriods might be involved.
Nitrogen dioxide is a major air pollutant and a deep lung irritant. Nitrogen dioxide is formed in combustion processes, either directly or through secondary oxidation of nitric oxide (8). Nitrogen dioxide causes pulmonary inflammation, lower levels of lung antioxidants (10), deterioration of respiratory defense mechanisms, and increases susceptibility to respiratory pathogens (8). Nitrogen dioxide can also increase the incidence and severity of respiratory infections, can reduce lung function, and can aggravate the symptoms of asthmatics or subjects with COPD (8). Nitric oxide can also combine with superoxide anions to form peroxynitrite, which can generate the highly reactive hydroxyl anion (OH). According to epidemiological studies, the population group most susceptible to these adverse effects is small children, either with and without asthma (8). This group develops respiratory illnesses, shortness of breath, persistent wheeze, chronic cough, chronic phlegm, and bronchitis (4-8). Even though asthmatic children have increased amounts of exhaled nitric oxide over non-asthmatic children, there is persuasive evidence that higher levels of nitric oxide are decreased by the overproduction of oxygen radicals during the inflammatory process (1-8). This becomes a problematic situation for which the only solution is denied by the circumstance inherent in the problem. The underlying chronic inflammatory process in asthma, which induces nitric oxide synthesis, also produces excess oxygen radicals, which will destroy nitric oxide (6). The inhalation of a pulmonary irritant has been shown to enhance nitric oxide production by alveolar macrophages in rats, which also produces an increased level of oxygen radical that can react directly with nitric oxide to produce NO2 (1-3, 6).
Sodium pyruvate is an antioxidant that reacts directly with oxygen radicals to neutralize them. In macrophages, and other cell lines, sodium pyruvate regulates the production and level of inflammatory mediators including oxygen radical production and also increases the synthesis of nitric oxide (9). It can specifically lower the overproduction of superoxide anions. Sodium pyruvate also increases cellular levels of glutathione, a major cellular antioxidant (12). It was recently discovered that glutathione is reduced dramatically in antigen-induced asthmatic patients (13) and inhaled glutathione does not readily enter cells. Pyruvate does enter all cells via a transport system and can also cross the blood brain barrier. Excess sodium pyruvate beyond that needed to neutralize oxygen radicals will enter the bronchial and lung cells. All cells have a transport system that allow cells to concentrate pyruvate at higher concentrations than serum levels. In the cell, pyruvate raises the pH level, increases levels of ATP, decreasing levels of ADP and cAMP, and increases levels of GTP, while decreasing levels of cGMP. Nitric oxide acts in the opposite mode by increasing levels of cGMP and ADP, and requires an acid pH range in which to work (19).
U.S. Pat. No. 6,063,407 (Zapol et al.) discloses methods of treating, inhibiting or preventing vascular thrombosis or arterial restenosis in a mammal. The methods include causing the mammal to inhale a therapeutically effective concentration of gaseous nitric oxide. Also disclosed are methods that include the administration of the following types of agents in conjunction with inhaled nitric oxide: compounds that potentiate the beneficial effects of inhaled nitric oxide, and antithrombotic agents that complement or supplement the beneficial effects of inhaled nitric oxide.
U.S. Pat. No. 6,020,308 (Dewhirst et al.) discloses the use of an inhibitor of NO activity, such as a nitric oxide scavenger or an NO synthase inhibitor, as an adjunct to treatment of inappropriate tissue vascularization disorders
U.S. Pat. No. 5,891,459 (Cooke et al.) discloses the maintenance or improvement of vascular function and structure by long term administration of physiologically acceptable compounds, such as L-arginine, L-lysine, physiologically acceptable salts thereof, and polypeptide precursors thereof, which enhance the level of endogenous nitric oxide or other intermediates in the NO induced relaxation pathway in the host. In or in combination, other compounds, such as B6, folate, B12, or an antioxidant, which provide for short term enhancement of nitric oxide, either directly or by physiological processes may be employed.
U.S. Pat. No. 5,873,359 (Zapol et al.) discloses a method for treating or preventing bronchoconstriction or reversible pulmonary vasoconstriction in a mammal, which method includes causing the mammal to inhale a therapeutically effective concentration of gaseous nitric oxide or a therapeutically effective amount of a nitric oxide releasing compound, and an inhaler device containing nitric oxide gas and/or a nitric oxide releasing compound.
U.S. Pat. No. 5,767,160 (Kaesemeyer) discloses a therapeutic in vitro or in vivo mixture comprising L-arginine and an agonist of nitric oxide synthase, such as nitroglycerin for the treatment of diseases related to vasoconstriction. The vasoconstriction is relieved by stimulating the constitutive form of nitric oxide synthase (cNOS) to produce native nitric oxide. The native NO has superior beneficial effect when compared to exogenous NO produced by a L-arginine independent pathway in terms of the ability to reduce clinical endpoints and mortality.
U.S. Pat. No. 5,543,430 (Kaesemeyer) discloses a therapeutic mixture comprising a mixture of L-arginine and an agonist of nitric oxide synthase such as nitroglycerin for the treatment of diseases related to vasoconstriction. The vasoconstriction is relieved by stimulating the constitutive form of nitric oxide synthase to produce native nitric oxide. The native NO has superior beneficial effect when compared to exogenous NO produced by a L-arginine independent pathway in terms of the ability to reduce clinical endpoints and mortality.
U.S. Pat. No. 5,428,070 (Cooke et al.) discloses a method for treating atherogenesis and restenosis by long term administration of physiologically acceptable compounds which enhance the level of endogenous nitric oxide in the host. Alternatively, or in combination, other compounds may be administered which provide for short term enhancement of nitric oxide, either directly or by physiological processes. In addition, cells may be genetically engineered to provide a component in the synthetic pathway to nitric oxide, so as drive the process to enhance nitric oxide concentration, particularly in conjunction with the administration of a nitric oxide precursor.
U.S. Pat. No. 5,286,739 (Kilbourn et al.) discloses an anti-hypotensive formulation comprising an essentially arginine free or low arginine (less than about 0.1%, most preferably, about 0.01%) containing a mixture of amino acids. The formulation may include ornithine, citrulline, or both. A method for prophylaxis and treatment of systemic hypotension in an animal is also provided. A method for treating hypotension caused by nitric oxide synthesis through administering a low or essentially arginine free parenteral formulation to an animal, so as to reduce or eliminate nitric oxide synthesis is described. A method for treating an animal in septic shock is also disclosed, comprising administering to the animal an anti-hypotensive formulation comprising a mixture of amino acids, which is essentially arginine free. Prophylaxis or treatment of systemic hypotension, particularly that hypotension incident to chemotherapeutic treatment with biologic response modifiers, such as tumor necrosis factor or interleukin-1 or 2, may be accomplished through the administration of the defined anti-hypotensive formulations until physiologically acceptable systolic blood pressure levels are achieved in the animal. Treatment of an animal for septic shock induced by endotoxin may also be accomplished by administering to the animal the arginine free formulations described.
U.S. Pat. No. 5,217,997 (Levere et al.) discloses a method for treating a high vascular resistance disorder in a mammal by administering to a mammalian organism in need of such treatment a sufficient amount of L-arginine or pharmaceutically acceptable salt thereof to treat a high vascular resistance disorder. The L-arginine is typically administered in the range of about 1 mg to 1500 mg per day. High vascular resistance disorders include hypertension, primary or secondary vasospasm, angina pectoris, cerebral ischemia and preeclampsia. Also disclosed is a method for preventing or treating bronchial asthma in a mammal by administering to a mammalian organism in need of such prevention or treatment a sufficient amount of L-arginine to prevent or treat bronchial asthma.
U.S. Pat. No. 5,158,883 (Griffith) discloses pharmaceutically pure physiologically active NG-aminoarginine (i.e., the L or D, L form), or pharmaceutically acceptable salts thereof, administered in a nitric oxide synthesis inhibiting amount to a subject in need of such inhibition (e.g., a subject with low blood pressure or needing immunosuppressive effect) or added to a medium containing isolated organs, intact cells, cell homogenates or tissue homogenates in an amount sufficient to inhibit nitric oxide formation to elucide or control the biosynthesis, metabolism or physiological role of nitric oxide. The NG-amino-L-arginine is prepared and isolated as a pharmaceutically pure compound by reducing NG-nitro-L-arginine, converting L-arginine by-product to L-ornithine with arginase and separating NG-amino-L-arginine from the L-ornithine. NG-amino-D,L-arginine is prepared in similar fashion starting with NG-nitro-D,L-arginine.
U.S. Pat. Nos. 5,798,388, 5,939,459, and 5,952,384 (Katz) pertain to a method for treating various disease states in mammals caused by mammalian cells involved in the inflammatory response and compositions useful in the method. The method comprises contacting the mammalian cells participating in the inflammatory response with an inflammatory mediator. The inflammatory mediator is present in an amount capable of reducing the undesired inflammatory response and is an antioxidant. The preferred inflammatory mediator is a pyruvate. Katz discloses the treatment of airway diseases of the lungs such as bronchial asthma, acute bronchitis, emphysema, chronic obstructive emphysema, centrilobular emphysema, panacinar emphysema, chronic obstructive bronchitis, reactive airway disease, cystic fibrosis, bronchiectasis, acquired bronchiectasis, kartaagener""s syndrone; atelectasis, acute atelectasis, chronic atelectasis, pneumonia, essential thrombocytopenia, legionnaires disease, psittacosis, fibrogenic dust disease, diseases due to organic dust, diseases due to irritant gases and chemicals, hypersensitivity diseases of the lung, idiopathic infiltrative diseases of the lungs and the like by inhaling pyruvate containing compositions. The pyruvate acts as an inflammatory response mediator and reduces the undesired inflammatory response in mammalian cells.
U.S. Pat. No. 5,296,370 (Martin et al.) discloses therapeutic compositions for preventing and reducing injury to mammalian cells and increasing the resuscitation rate of injured mammalian cells. The therapeutic composition comprises (a) pyruvate selected from the group consisting of pyruvic acid, pharmaceutically acceptable salts of pyruvic acid, and mixtures thereof, (b) an antioxidant, and (c) a mixture of saturated and unsaturated fatty acids wherein the fatty acids are those fatty acids required for the resuscitation of injured mammalian cells.
While the above therapeutic compositions and methods are reported to inhibit the production of reactive oxygen intermediates, none of the disclosures describe methods for treating a pulmonary disease state in mammals by altering indigenous in vivo levels of nitric oxide in mammalian cells.
The present invention pertains to a method for treating a pulmonary disease state in mammals by altering indigenous in vivo levels of nitric oxide in mammalian cells. The method comprises contacting the mammalian cells with a therapeutically effective amount of a nitric oxide mediator selected from the group consisting of pyruvates, pyruvate precursors, xcex1-keto acids having four or more carbon atoms, precursors of xcex1-keto acids having four or more carbon atoms, and the salts thereof.
The method may further comprise contacting the mammalian cells with a nitric oxide source selected from the group consisting of nitric oxide, nitric oxide precursors, and nitric oxide stimulators. The method still may further comprise contacting the mammalian cells with a therapeutic agent such as antibacterials, antivirals, antifungals, antihistamines, proteins, enzymes, hormones, nonsteroidal anti-inflammatories, cytokines, or steroids. The method may still further comprise contacting the mammalian cells with both a nitric oxide source and a therapeutic agent.